Method of electric arc welding pipe



Nov. 10, 1931. H. J. BURNISH 1,830,783

METHOD OF ELECTRIC A'Rc WELDING PIPE Filed Aug. 31. 1929 FIG; 1.

INVENTOR.

Howard JIBumz'sh A TTORNEY.

meme m 10, 1931 UNITED STATES PATENT OFFICE EDWARD J. FURNISH, OI MILWAUKEE, WISCONSIN, ASSIGNOR TO A. 0. SMITH COR- PORATION, OI MILWAUKEE, WISCONSIN, A CORPORATION OF NEW YORK METHOD OF ELECTRIC ARC WELDING PIPE Application filed August 81, 1929. Serial No. 389,854.

This invention relates to a method of electric arc welding and has particular applica- The pipe blank 1 is preferably formedtion to the arc welding of longitudinal seams in tubular articles such as pipe.

The object of the invention is to provide a method of arc welding the longitudinal seam of a tubular article wherein a uniform weld will be obtained near the respective ends of the article as comparedv with the weld at the central portion thereof.

Another object is to obtain uniform penetration of the weld throughout the length of the pipe.

Other objects will appear hereinafter 1n connection with the preferred embodiment of the invention as illustrated in the accompanying drawings in which the" views are as ollows: a

Figure 1 is a top plan view of a pipe blank 26 showing the seam to be welded.

Fig. 2 is a transverse sectionon line 2-2 of Fig.1 showing the welding operation.

Fig. 3 is a longitudinal section of the finished weld on line 3-3 of Fig. 1.

from a flat sheet of metal, the side edges 2 of the sheet meeting on a longitudinal line of the'blank. The edges 2 are chamfered to form a welding groove 3 for receiving de- 3 posited welding metal 4.

The welding metal 4 is deposited by means of an electric are 5 established between a fusible metallic weldrod 6 which furnishes the metal 4, and the edges 2 to be welded.

The metal of the weldrod 6 is projected by the are into the welding groove 3 and is fused with the metal of the edges 2 to weld the same together. The weldrod is fed-to the are at a rate commensurate with the rate of consumption of the weldrod metal in order to maintain the are. The feeding of the weldrod is preferably accomplished by employing an automatic feeding mechanism represented as at 7 which is responsive to changing characteristics of the arc to maintain varying rates of feed of the weldrod.

It has been found that these characteristics of the are are affected by magnetic flux con-' The varying characteristics of the 'arc which are caused by changing magnetic flux conditions in the pipe interfere with the feeding mechanism 7 in a manner to maintain a different arc length when welding near the ends of the pipe than the welding in the central portion of the pipe. lack of proper penetrationof the weld and a lack of proper fusion of the metal of the weld near the ends of the pipe. 2

Due to the difficulties above mentioned it has not heretofore been general practice to employ automatic welding machines to weld the entire length of the seam. Instead, where uniform strong welds were required, it

has been customary to hand Weld the ends tion of the seam by employing automatic welding machines.

The present invention obviates this neces- The result is a til) sity and enables the employment of automatic welding machines for the full length of the seam without detriment to the quality of the weld.

This is accomplished by spacing the edges to be welded a predetermined amount at each end while maintaining them in closer relation and preferably in contact throughout the intermediate portion of the seam, as shown in Figure 1.

The increased spacing of the edges at the ends of the seam facilitates the penetration of the weld and thereby provides a uniform penetration of the weld throughout the full length of the seam irrespective of var ing characteristics of the arc. This uni orm penetration of the weld is illustrated in Fig. 3.

The invention may have various modifications within the scope of the claims.

.1 claim:

1. The method of electric arc welding longitudinal seams in tubular articles comprising shaping the end portions of an edge 4 line of the edge, placing the intermediate portion of the two edges forming the seam m welding proximity and causing the recedter ' sive to changes in characteristics of the arc.

3.'In electric arc welding a lon 'tudinal' .rod to to be welded so as to recede from the. normal ing end portions to form relatively spacesbetween the edges at their en than between the central ortions of the same, and ap lying an electric arc to progressively weld the edges throughout the full length thereof.

2. The method of electric arc welding longitudinal seams in tubular articles comprising providing a space between the edges to be welded near the ends thereofwhile maintaining the intermediate portion of the edges in contact, establishing an. electric are between the edges and a sible metallic weld- Brogressively fuse and weld the edges throug ing. the weldrod to the are at a rate responseam in avtu bular article, the step 0 providing a greater separation of the edges at the end portions of the seam than intermediate the said end portions to facilitate maintaining auniform penetration of the weld throughout the length of the seam.

In witness whereof I have signed my name at Milwaukee, Wisconsin, this 26th day of August, 1929. a HOWARD J. BURNISH.

out the length of the seam, and feed 

